Page:Science vol. 5.djvu/320

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��IVoi. T., No. IM!

��by ilie Hounc] Arising frnni sliaking roiU nilliin it, Mr. Andrew lUddow, the engineer, lowered four elgbUincli b»r-iiiigiieU (placed end to end, with the south pole down) into the bom. The norlli pole of a eompaBS-neeiDe in the mine moved Brst to the west, and then to the east, of magnetic north, t-t the mag- net* were lowered. Indicating that the mtigiielB were to the westward of Uic compau. While the heading was Iwing enlarged in this direction, ilr. Haddow experimented by passing a magnet around the com- pass, and drawing a aerien of curves for positions of the magnet, which produced different angular detleic- tions of the needle. The cotnpasn was Iht^n placed successively at two different points in the heading, and the deflections causeil by the magnets In the bore-hole were noted, — at one point Uj°. at the other 6)°. The two points were then marked on the plan of the mine, a tracing of the magnetic carves just referred to was placed over each point, and tlic intersection of the curves corresponding to these deflections was noted. ITpon excavnling to Ihe point thus iadlcaled, the bore was found, iKing about eight feet from the true vertical.

In a second case, in Australia, the diamond drill, In going down three hundred ami seventy feet, had deviated beyond sensible magnetic influence, Aui the search by undei^round mining was continued for nearly twelve months without success. Mr E. P. Hacge'irge then employed glass phials partly filled with melted gelatine, and having a com pnss- needle in a lower connected bulb of the phial. Wlien these were carefully lowei-eil in the bore to ditlerunl depths, and the gelatine congealed, the needle would hecottie fixed in the magnetic nortli, and the surface of the gelatine would be horizontal. These two indications, wlien the phial was wlllidrawn, showed Ihe inclina- tion and magnetic bearing of the bore-lioie at that point; and a sutlicient number of observations at convenient depths permitted the erratic bore-iiole to be completely nappi'd from top to bottom. Thl.i map showed a deviation of nearly forty feet at three hundred and seventy feet down (the point so long searched for), and of between seventy and eighty feet at the full deptli of five hundred feet. A drift straight for the Indicated spot found the lost lian> thirty-seven feet and a half away from its prot^er place, and the bottom was found seventy-five fiet astray. This device has since lieen perfected and patented.

FISUING-INTERESTS IN HUDSON BAY.

TUK chief commercial value of tills district nn- doubtedly lies iu Its immense flshlng-inte rests, if we Include in that term whaling and sealing.

American whaling- vessels have tor more tliBD a quarter of a century been conducting a very proflt- able fishery In Roe's Welcome, a large basin in the norlh-westeru portion of Hudson Bay. The vessels usually leave New England in July, and reacli Marble Island In September, where they winter, one or two every season, an<l occasionally more. Sawing out of the ice ill Ihe fi'Ilnwing .lune, and prr-wing norlhward

��as fast as the ice will permit, they fish until abiWL the first of September, unless sooner loaded, and then sail for home. During the eleven years preced- ing 1874, about fifty voyages are known to have been made ; and the returns give an average of $27,420 per voyage, which shows a lai^e margin of profit to tlip small sailing- vessels usually engaged In the trade. It is estimated that the aggregate value of oil and whalebone already obtained is about two and a quar- ter million dollars, and every thing points to a Urge extension of the industry.

The porpoise-li^hery is extensively carrie<l on by the Hudson-Bay company; the fish, as they are popu- larly called, being held in check by means of trap- nets on flats In coves where the tide rises ten or fifteen feet, and left high and dry when the water recedes. Last year the company secured neariy two hundred in one tide at Churcliill. and a mucb larger number at Dngava Bay. The blubber weighs from two liundred and fifty to four hundred pound!,; and is very rich in llie finest of oil. Formerly tlM blubber was exported; but the company has esl«b- llshed extensive refineries at several of its nurlhem stations, and now ships the oil in casks.

The company also carries on a wainis-himt. send- ing two sloops annually from Churchill to two very productive walrus-grounds nortli of Marble Island, where they have never failed to obtain full cargoes of bliiliber, ivory, and hides in a few weeks, besides carrying on a valuable trade in oil, ivory, musk-ox. and other skins, with the northern E^iino.

During the exploring-steamer Neptune's visit to Stupart's Bay, the Eskimo were Itving uii llie barp- senl (Phoca groeniandica Llnnd), and had in their potsessiou skins of a good many harbor and sijuare- flipper seals (Pttoca vitullna Llun^, and Erignathua barbatus Fahriciiis), seals of alt ktnd4 being abun-

The Hudson-Bay company baa a steamer, Hi* Diana, plying between London and Ungava Bay di- rect, fitted up with refrigerating apparatus, and en- gaged solely in conveying salmon fresh lulbe London market. IjhsI year's cargo is reported to have real- ized eighteen thousand dollars. Nearly every stream contains both salmon and trout in vast quantities, chiefly where the salt and fresh waiert mingle.

Co<l abound In the vicinity of Chudieigh. tlinugh not up to the present time found in Hudson Bay. Newfoundland schooners even now work as far north as Nachvak, and seem to be going farther each year. The cod, though good, are not equal to tliosu of Iha l^anks. ^Vhile the Neptune was at Tort Burwell, iKith In going niid on returning, the anchorage tei^raed wlib cod, which were taken In great numb«n by jigging from the ship's deck.

��THE DRAINAnE SYSTEM OF

TiiK hydrographic features of Brazil are t Iain extent iletermlned by the orographic system, i by ibe distribution of mountains and plains detcribt

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